The present invention relates to vehicle entranceways and exitways and, particularly, to stowable ramps associated therewith for facilitating the passage therethrough of wheelchairs and persons unable to negotiate one or more steps up into the vehicle.
There has long been a need for an extendible ramp at the entranceway of a motor bus, for example, over which a wheelchair passenger or other handicapped person might traverse in entering or leaving the vehicle at a bus stop. Several years ago, Donald L. Manning was granted U.S. Pat. No. 4,131,209 covering such an extendible ramp device. An improvement patent U.S. Pat. No. 4,685,858 was granted to Manning and Hood on Aug. 11, 1987. A further improvement is shown in copending U.S. application Ser. No. 046,402--Hood, filed 5-6-87 now U.S. Pat. No. 4,759,682. The present device is an improvement in certain aspects of the earlier ramp designs.
In the earlier ramp designs, a bell crank and power piston mechanism was utilized to lift the inner end of the ramp to vehicle floor level when the ramp was in its extended position outward of the vehicle. The present invention eliminates the bell crank and power piston mechanisms and instead utilizes a simplified inclined track and roller system to raise the inner end of the ramp as it approaches its extended position.
The present invention also includes a pivotal step riser spring-biased to its normal or vertical position when the ramp is retracted and a cam/follower device actuated by the ramp to position the riser upon the ramp when the latter is in its extended position.
Finally, the present invention includes a sensitive edge articulated transversely to the outer end of the ramp to provide a smooth transition from the extended ramp to the ground. The improvement in such sensitive edge including a spring member for extending the edge to a generally coplanar position relative to the upper ramp surface when the ramp is extended and a cam/follower device for rotating the edge from its coplanar position when the ramp is retracted.